HELP 1988 300e no power to ac compressor
Thread Starter
Newbie
Joined: May 2004
Posts: 10
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From: Alabama
1988 300E
HELP 1988 300e no power to ac compressor
Hello, I have a 1988 300e that i have in the shop trying to resolve an AC problem. I have had the car for several years and drove it without the AC, however I have now decided to pass the car on to my son and need to get the AC fixed. The car is at the shop and the mechanic is telling me that the Compressor is fine but there is no power getting to the AC by the normal means. Are there any suggestions on what I might be dealing with, and how I should troubleshoot to resolve the issue. I am also having problems with the ignition switch sticking when turned to the on and off position. However the AC problems has been a problem before the sticking switch. I wanted to mention this just in case.
Thanks in advance for any assistance anyone can provide.
bigchat1
1988 300e
2001 E320 Sport
1976 230 - Down with bad engine
Thanks in advance for any assistance anyone can provide.
bigchat1
1988 300e
2001 E320 Sport
1976 230 - Down with bad engine
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
Hello, I have a 1988 300e that i have in the shop trying to resolve an AC problem. I have had the car for several years and drove it without the AC, however I have now decided to pass the car on to my son and need to get the AC fixed. The car is at the shop and the mechanic is telling me that the Compressor is fine but there is no power getting to the AC by the normal means. Are there any suggestions on what I might be dealing with, and how I should troubleshoot to resolve the issue. I am also having problems with the ignition switch sticking when turned to the on and off position. However the AC problems has been a problem before the sticking switch. I wanted to mention this just in case.
Thanks in advance for any assistance anyone can provide.
bigchat1
1988 300e
2001 E320 Sport
1976 230 - Down with bad engine
Thanks in advance for any assistance anyone can provide.
bigchat1
1988 300e
2001 E320 Sport
1976 230 - Down with bad engine
Regarding the AC, if the charge is low there will be no power to the compressor because the low pressure switch contacts will be open. If there is no power to the low pressure switch then that is another problem. That could be an open low temp cutout switch, or a problem with the HVAC controls.
Thread Starter
Newbie
Joined: May 2004
Posts: 10
Likes: 0
From: Alabama
1988 300E
Thanks for all the replys, I will check any an all fuses and any help with the diagram would be helpful
In reference to the open low temp cutout switch, where is that located and what is the best way to troubleshoot to determine if it is bad The HVAC, i have heard it before, but can not remember what the acornym stands for.
In reference to the open low temp cutout switch, where is that located and what is the best way to troubleshoot to determine if it is bad The HVAC, i have heard it before, but can not remember what the acornym stands for.
Thread Starter
Newbie
Joined: May 2004
Posts: 10
Likes: 0
From: Alabama
1988 300E
IF the ac was charged could it be that the lower Pressure switch is bad? Also what is the best way to eliminate that it is the control unit in the dash where the climate control dial is and the ac on/off button is. I quess that i really need to locate a diagram and troubleshoot it with a ohm meter.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
Likes: 1
From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
IF the ac was charged could it be that the lower Pressure switch is bad? Also what is the best way to eliminate that it is the control unit in the dash where the climate control dial is and the ac on/off button is. I quess that i really need to locate a diagram and troubleshoot it with a ohm meter.
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Thread Starter
Newbie
Joined: May 2004
Posts: 10
Likes: 0
From: Alabama
1988 300E
Thnaks so much for your help. I will try this, let me know if anything else comes to mind. thanks to all, and Please continue to post if you have any ideas of what i might be dealing with
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From: Mexico Beach FL
2007 S65 AMG, 1997 SL500
How does the shop know the compressor is fine if there is no power to it? Plus why can't they figure out why it has no power? Find another shop that knows what they are doing. When I got my old 1988 300E at a garage sale the AC wasn't working. After troubleshooting here is what I found:
Compressor clutch failed and went to ground. Ohms to ground = zero. This caused an excessive current draw on the clutch control circuit (CCC) which burned up a resistor on the board inside the KLIMA relay. The KLIMA relay controls the AC compressor clutch and is located near the battery. I took the KLIMA relay apart and could see the burned resistor. Bought a used KLIMA relay, rebuilt compressor, and a drier on Ebay. Installed all and added an inline fuse in the wire from the KLIMA relay to the AC clutch. (Incredibly enough these overengineered cars DO NOT have a fuse protecting this expensive relay....if the clutch grounds it will toast the KLIMA), recharged the system and it has worked fine for 3 years....also I have never blown the inline fuse I installed.
I got the car cheap because w/o AC the dark red interior made it UNBEARABLE to drive in Atlanta during the summer.
Compressor clutch failed and went to ground. Ohms to ground = zero. This caused an excessive current draw on the clutch control circuit (CCC) which burned up a resistor on the board inside the KLIMA relay. The KLIMA relay controls the AC compressor clutch and is located near the battery. I took the KLIMA relay apart and could see the burned resistor. Bought a used KLIMA relay, rebuilt compressor, and a drier on Ebay. Installed all and added an inline fuse in the wire from the KLIMA relay to the AC clutch. (Incredibly enough these overengineered cars DO NOT have a fuse protecting this expensive relay....if the clutch grounds it will toast the KLIMA), recharged the system and it has worked fine for 3 years....also I have never blown the inline fuse I installed.
I got the car cheap because w/o AC the dark red interior made it UNBEARABLE to drive in Atlanta during the summer.
